261339571 has 2 divisors, whose sum is σ = 261339572. Its totient is φ = 261339570.

The previous prime is 261339523. The next prime is 261339577. The reversal of 261339571 is 175933162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261339571 - 2¹³ = 261331379 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261339571.

It is not a weakly prime, because it can be changed into another prime (261339577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130669785 + 130669786.

It is an arithmetic number, because the mean of its divisors is an integer number (130669786).

Almost surely, 2^261339571 is an apocalyptic number.

261339571 is a deficient number, since it is larger than the sum of its proper divisors (1).

261339571 is an equidigital number, since it uses as much as digits as its factorization.

261339571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34020, while the sum is 37.

The square root of 261339571 is about 16166.0004639367. Note that the first 3 decimals coincide. The cubic root of 261339571 is about 639.3446832328.

The spelling of 261339571 in words is "two hundred sixty-one million, three hundred thirty-nine thousand, five hundred seventy-one".